It is known in the art to employ amplification systems to modify the signal generated by a musical instrument, e.g., a guitar, for playback of such modified signal through a loud speaker. Various types of amplification systems are commercially available, including amplifiers based upon solid-state components, and amplifiers based upon vacuum tube components. The latter type of amplifier will be made reference to in this disclosure as a “tube-type” amplifier.
The sound quality of a musical instrument is known to be effected by the type of amplification system used in playback of the instrument through a speaker system. Certain performers prefer the sound quality that may be delivered by tube-type amplifiers. The perceived sound quality typically includes a certain amount of inherent distortion and a range of modifications that may be made to an instrument's generated musical signal by certain signal-manipulating circuitry.
Certain known amplification systems and related circuitry, which are relevant to the instant invention, are disclosed in U.S. Pat. Nos. 7,053,714; 6,111,961; 5,550,509; 5,550,508; 5,546,046; 4,864,245; 4,644,289; and 4,636,740. A distortion-inducing circuit for application in an amplifier system is disclosed in Unites States Patent Application Serial No. 2006/0012424. The entire disclosures of the aforementioned publications are hereby incorporated as though set forth herein in full for their teachings of amplification systems and related circuitry.
It would be an advance in the art to provide a tube-type musical amplifier capable of producing a musical signal for playback through a speaker system at a plurality of volume levels, but which produces a sound at each such volume level that is much closer to the sound of the amplifier “on ten,” or at its maximum volume setting.